Hydrowype A-Series Rod Scrapers
A-Series Rod Scrapers are manufactured to the MS28776 specification in accordance with the MIL-S-5049 procurement standard.
Over the years, different manufacturers have produced scrapers that conform to the MS28776 specification, with minor variances, primarily in their means of achieving rod conformance and controlling breakout friction. The spec permits both multi-part and single part styles of scrapers. Table 1 of MIL-R-5049 specifies material options. Certain materials that have some desirable characteristics but need the assistance of a spring (multi-part configuration) to maintain the required rod contact while controlling break-out friction to within the specified limits. To assist customers in maintaining the continuity of their designs, Hydrowype mil-spec scrapers are available in the following:
- -M2 Versions:
- a solid scraping body only (Style-I)
- a scraping body with a narrow groove accommodating a serpentine form spring to scraping load (Style-II and IV)
- a scraping body with a wide groove in the outside diameter accommodating two “c” style springs (resembling split washers) to generate scraping load (Style-III)
- -R2 Versions:
- a scraping body with elastomer band either trapped inside a metal retaining band (Style-V), or acting with interference on the housing counterbore (Style-VI)
The MS28776-R2 Variant is available only in Style-II, and substitutes a Rubber energizing band for the serpentine spring.
All styles are cadmium plated with gold chromate to QQL-614 and are inspected for required radial pressure, breakout friction and rod light-tightness per spec. Please note, Styles II, III wipers fully meet MIL-R-5049D and these must be bid on government procurements. Hydrowype certifies and will arrange on-site inspection by our assigned QAR.